Repair of a Failed Slope Using Geogrid Reinforcement

Slope failures often occur in highways located in the mountainous terrain of Northern Thailand. There are several factors which induce those failures. The construction material consists of cohesionless decomposed granite. The highway embankment is steep over 30 m in height. The rainfall is very high during the monsoon season. Due to limitation of right of way, difficulty in the reconstruction and environmental consideration, geogrid reinforced embankment is introduced. The advantages of using the reinforced structure are to use less material because the very steep slope can be maintained and the vegetative cover is feasible. However, the method is expensive, economical design is necessary, i.e., very steep slope, wide spacing of geogrid and the minimum length of geogrid. The research was commenced on a selected failed slope repaired by using geogrid reinforcement. Borings were performed with soil samples taken to our laboratory to determine the engineering properties of the embankment materials as well as the soil profile of the foundation. The design and construction was verified by installing several geotechnical instruments, i.e., inclinometers, piezometers, observation wells, surface settlement plates and pressure cells. Long term monitoring data were recorded and analyzed. The FEM model was established and calibrated with measuring data. The analysis results indicated that surface runoff and seepage were the major causes of the failure. In order to prevent the future failure, good surface drainage is required to eliminate the surface runoff and the horizontal drainage pipes are needed to reduce the amount of underground water. The FEM analysis shows that using the geogrid reinforcement improves the slope stability; however, the length of geogrid should be long enough in order to fully develop the anchorage end

Dietary patterns and their association with the components of metabolic syndrome: A cross-sectional study of adults from northeast Thailand [version 2; peer review: 2 approved]

Background: Nutritional transition influences a shift in eating behaviour that is associated with a rise in the prevalence of non-communicable diseases (NCDs). Metabolic syndrome (MetS) comprises a set of NCD risk factors. This study aimed to investigate dietary patterns and to determine the relationship between dietary patterns and MetS and its components. Methods: An analytical cross-sectional study was conducted among 468 adults aged 35–60 years who were residents of a semi-urban district of one of the central provinces in the northeast of Thailand. A factor analysis identified dietary patterns based on the consumption of 21 food groups, which were assessed by using a semi-quantitative food frequency questionnaire. MetS was identified by using the harmonized criteria that were stipulated by six leading international organisations. The association between dietary patterns and MetS and its components were evaluated by multiple logistic regressions. The confounding factors adjusted in the model were age, sex, smoking status, physical activity, and medication intake. Results: Two dietary patterns were identified: a traditional pattern characterised by high intakes of sticky rice and animal source foods; a mixed pattern included high intakes of white rice and a variety of food groups. The two dietary patterns did not show any association with MetS. Participants in the highest tertile of the traditional pattern was significantly related to high triglycerides (adjusted OR = 1.74, 95% CI: 1.10–2.88), in comparison to those from the lowest tertile, whereas participants in the highest tertile of the mixed pattern was inversely associated with abdominal obesity (adjusted OR= 0.49, 95% CI: 0.30–0.81) than those in the lowest tertile. Conclusions: Adherence to a traditional dietary pattern among the northeast Thai adults, in the context of nutrition transition, was associated with high triglyceride levels while the mixed dietary pattern was inversely related to abdominal obesity

Flexural characteristics of rubberized cement-stabilized crushed aggregate for pavement structure

The purpose of this paper is to investigate the flexural characteristics and to quantitatively study the flexural-induced cracking of reference and rubberized cement stabilized aggregate mixtures. Four volumetric replacement percentages (0%, 15%, 30% and 45%) of 6 mm fraction size were used. This modification was found to affect the material strength detrimentally. However, material toughness was improved and stiffness was reduced. The latter findings were supported by quantitative assessment of the fractured surfaces which revealed more tortuous and rougher cracking as a result of rubber content increasing. This, in turn, may ensure a good load transfer across the cracks after their formation. Overall, using rubber in pavement construction is a sustainable solution that ensures consumption of large quantities of these waste materials. At the same time, it may be considered as a promising method to reduce cracking tendency and sensitivity which may improve shrinkage, thermal and fatigue performance

Characterization of Concrete Pavement Joint Surfaces

129 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2005.In many concrete structures especially pavements, the ability to transfer shear load across crack/joint and the cracking resistance are important. This research was conducted in order to develop a testing method and roughness parameter that could better predict the shear load transfer across crack/joint. In addition, the research intended to improve both the joint shear stiffness and concrete cracking resistance through the selection of proper concrete constituents. In the study, fractured concrete surfaces resulting from various aggregate types, sizes and gradations were manufactured. A 2D laser profiling device was developed to capture the fractured surface profiles. Existing surface parameters, such as surface roughness number, volumetric surface texture ratio and fractal dimension, were calculated to represent the surface's roughness. The study showed weak to no correlation between the existing roughness parameters and the shear load transfer ability. Therefore, a new surface parameter called Power Spectral Area Parameter was developed and validated in order to better predict the shear load transfer across crack/joint. Wedge splitting test was conducted in order to correlate the concrete's fracture energy with the shear transfer ability. The fracture energy was able to represent both the concrete's fractured surface and shear load transfer properties for several coarse aggregate types and sizes. Strong, large and gap-graded coarse aggregates could improve concrete joint and cracking performances compared with weaker, smaller-sized and dense-graded aggregate mixes.U of I OnlyRestricted to the U of I community idenfinitely during batch ingest of legacy ETD